U.S. patent number 8,655,238 [Application Number 13/861,271] was granted by the patent office on 2014-02-18 for developing member.
This patent grant is currently assigned to Canon Kabushiki Kaisha. The grantee listed for this patent is Canon Kabushiki Kaisha. Invention is credited to Takashi Kusaba, Ryo Sugiyama, Masashi Uno, Shohei Urushihara.
United States Patent |
8,655,238 |
Uno , et al. |
February 18, 2014 |
Developing member
Abstract
Provided is a developing roller including elastic layer and
resin layer adhered to each other and having an appropriately
resistance, thereby suppressing fogging. The developing member
comprises a mandrel; an elastic layer; and a resin layer, wherein:
the resin layer comprises polyurethane resin obtained by isocyanate
and polyol; and the elastic layer includes cured silicone rubber
composition comprising (a)-(d): (a) organopolysiloxane having two
or more alkenyl groups bonded to silicon atom and having methyl
group as a group other than the alkenyl bonded to the silicon; (b)
organopolysiloxane having three or more hydrogen atoms bonded to
silicon atom and having methyl group as a group bonded to the
silicon; (c) carbon black; (d) organopolysiloxane represented by
formula (1) and having Mw of 18,000-110,000 and Mw/Mn of 1.0-2.0
(R.sup.1 represents alkenyl group, R.sup.2 represents functional
group reacting with isocyanate, and n represents an integer of 1 or
more). ##STR00001##
Inventors: |
Uno; Masashi (Mishima,
JP), Kusaba; Takashi (Suntou-gun, JP),
Urushihara; Shohei (Suntou-gun, JP), Sugiyama;
Ryo (Mishima, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Canon Kabushiki Kaisha |
Tokyo |
N/A |
JP |
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Assignee: |
Canon Kabushiki Kaisha (Tokyo,
JP)
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Family
ID: |
48573816 |
Appl.
No.: |
13/861,271 |
Filed: |
April 11, 2013 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20130223892 A1 |
Aug 29, 2013 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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PCT/JP2012/007388 |
Nov 16, 2012 |
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Foreign Application Priority Data
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Dec 9, 2011 [JP] |
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2011-270638 |
Nov 13, 2012 [JP] |
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2012-249648 |
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Current U.S.
Class: |
399/286 |
Current CPC
Class: |
G03G
15/0818 (20130101); G03G 15/08 (20130101) |
Current International
Class: |
G03G
15/08 (20060101) |
Field of
Search: |
;399/279,286 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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10-333422 |
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Dec 1998 |
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JP |
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11-12471 |
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Jan 1999 |
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JP |
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2004-126178 |
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Apr 2004 |
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JP |
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2005-300752 |
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Oct 2005 |
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JP |
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2009-138190 |
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Jun 2009 |
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JP |
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Other References
PCT International Search Report and Written Opinion of the
International Searching Authority, International Application No.
PCT/JP2012/007388, Mailing Date Dec. 18, 2012. cited by
applicant.
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Primary Examiner: Hyder; G. M.
Attorney, Agent or Firm: Fitzpatrick, Cella, Harper and
Scinto
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of International Application No.
PCT/JP2012/007388, filed Nov. 16, 2012, which claims the benefit of
Japanese Patent Applications No. 2011-270638, filed Dec. 9, 2011
and No. 2012-249648 filed Nov. 13, 2012.
Claims
What is claimed is:
1. A developing member, comprising in the following order: a
mandrel; an elastic layer; and a resin layer, wherein: the resin
layer comprises a polyurethane resin obtained by reacting an
isocyanate compound with a polyol compound; and the elastic layer
comprises a cured product of an addition polymerization type
silicone rubber composition comprising the following (a) to (d):
(a) an organopolysiloxane having two or more alkenyl groups bonded
to a silicon atom in one molecule and having a methyl group as a
group other than the alkenyl groups bonded to the silicon atom; (b)
an organopolysiloxane having three or more hydrogen atoms bonded to
a silicon atom in one molecule and having a methyl group as a group
bonded to the silicon atom; (c) carbon black; and (d) an
organopolysiloxane represented by the following formula (1) and
having a weight average molecular weight Mw of 18,000 or more and
110,000 or less and a molecular weight distribution Mw/Mn, where Mn
represents a number average molecular weight, of 1.0 or more and
2.0 or less: ##STR00004## in the formula (1), R.sup.1 represents an
alkenyl group having 2 or more and 4 or less carbon atoms, R.sup.2
represents a functional group capable of reacting with an
isocyanate group, and n represents an integer of 1 or more.
2. The developing member according to claim 1, wherein the
functional group capable of reacting with an isocyanate group in
the (d) component, comprises a group selected from the group
consisting of a hydroxyl group, an alkoxyl group, an amino group,
and a thiol group.
3. The developing member according to claim 2, wherein the
functional group capable of reacting with an isocyanate group in
the (d) component, comprises an alkoxyl group, and the alkoxyl
group comprises one of a methoxy group and an ethoxy group.
4. The developing member according to claim 1, wherein the (b)
component, has a weight average molecular weight of 300 or more and
100,000 or less.
5. The developing member according to claim 1, wherein the elastic
layer has a volume resistivity of 1.times.10.sup.4 .OMEGA.cm or
more and 1.times.10.sup.7 .OMEGA.cm or less.
6. An electrophotographic apparatus, comprising: a photosensitive
member; and a developing member placed to abut on the
photosensitive member, wherein the developing member comprises the
developing member according to claim 1.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a developing member and an
electrophotographic apparatus.
2. Description of the Related Art
As a developing system in an electrophotographic apparatus such as
a copier, a printer, or a receiving device of a facsimile, there
has been widely used a one-component developing system using
one-component toner.
As a developing member to be used in the developing system using
one-component toner, there has been known a configuration in which
an electro-conductive elastic layer containing silicone rubber in
which carbon black is dispersed is formed on an outer side of an
electro-conductive mandrel and a urethane resin layer is formed on
an outer side of the elastic layer.
In the developing member having a configuration in which the
elastic layer and the resin layer are laminated as described above,
there is a risk in that adhesiveness between the elastic layer and
the resin layer may be degraded due to a long-term use, and may
cause interfacial peeling between the elastic layer and the resin
layer.
Japanese Patent Application Laid-Open No. H11-012471 discloses a
developing roller in which a urethane resin layer is provided on a
silicone rubber layer via a primer containing
.gamma.-aminopropyltrimethoxysilane as its main component to
greatly enhance the adhesive strength between the silicone rubber
layer and the urethane resin layer.
SUMMARY OF THE INVENTION
However, according to the study conducted by the inventors of the
present invention, when a urethane layer was provided on a silicone
rubber layer, which had been made electro-conductive with carbon
black or the like, via a silane coupling agent as disclosed in
Patent Literature 1, the conductivity of the silicone rubber layer
was degraded in some cases.
In view of the foregoing, the present invention is directed to
providing a developing member excellent in adhesive strength
between an electro-conductive elastic layer containing carbon black
and silicone rubber and a surface layer containing a urethane resin
without impairing satisfactory conductivity of the elastic
layer.
Further, the present invention is directed to providing an
electrophotographic apparatus capable of stably providing a
high-quality electrophotographic image.
According to one aspect of the present invention, there is provided
a developing member, comprising in the following order: a mandrel;
an elastic layer; and a resin layer, wherein: the resin layer
comprises a polyurethane resin obtained by reacting an isocyanate
compound with a polyol compound; and the elastic layer comprises a
cured product of an addition polymerization type silicone rubber
composition comprising the following (a) to (d): (a) an
organopolysiloxane having two or more alkenyl groups bonded to a
silicon atom in one molecule and having a methyl group as a group
other than the alkenyl groups bonded to the silicon atom; (b) an
organopolysiloxane having three or more hydrogen atoms bonded to a
silicon atom in one molecule and having a methyl group as a group
bonded to the silicon atom; (c) carbon black; and (d) an
organopolysiloxane represented by the following formula (1) and
having a weight average molecular weight Mw of 18,000 or more and
110,000 or less and a molecular weight distribution Mw/Mn, where Mn
represents a number average molecular weight, of 1.0 or more and
2.0 or less.
##STR00002##
(In the formula (1), R.sup.1 represents an alkenyl group having 2
or more and 4 or less carbon atoms, R.sup.2 represents a functional
group capable of reacting with an isocyanate group, and n
represents an integer of 1 or more.)
According to another aspect of the present invention, there is
provided an electrophotographic apparatus, comprising: a
photosensitive member; and a developing member placed to abut on
the photosensitive member, wherein the developing member comprises
the above-described developing member.
According to the present invention, there is provided the
developing roller in which the silicone rubber elastic layer and
the polyurethane resin layer are firmly adhered to each other and
the electrical resistance are appropriately controlled, thereby
suppressing fogging.
Further features of the present invention will become apparent from
the following description of exemplary embodiments with reference
to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view illustrating an example of a developing
roller according to the present invention.
FIG. 2 is a schematic view of an apparatus for measuring an
electrical resistance of a developing roller according to the
present invention.
FIG. 3 is a schematic structural view illustrating an example of an
electrophotographic apparatus to which a developing roller obtained
by the present invention is applied.
DESCRIPTION OF THE EMBODIMENTS
Preferred embodiments of the present invention will now be
described in detail in accordance with the accompanying
drawings.
When a urethane resin layer is provided on a silicone rubber
elastic layer in which carbon black is dispersed via a silane
coupling agent, the conductivity of the silicone rubber elastic
layer is degraded. The cause for the degradation in conductivity is
not clear, but the inventors of the present invention presume the
cause as follows.
That is, a low-molecular-weight organic silane compound contained
in a silane coupling agent applied onto the surface of the elastic
layer permeates into the elastic layer. On the other hand, various
functional groups such as a hydroxyl group and a carboxyl group are
present on the surface of carbon black, and these functional groups
easily react with a reactive functional group of the
low-molecular-weight organic silane compound to form a chemical
bond. As a result, the carbon black is bonded to a cross-linking
structure of silicone rubber constituting the elastic layer, which
limits the movement of carbon black in the elastic layer.
In order for carbon black to function as an electro-conductive
agent, it is considered that it is necessary for particles of
carbon black to form a primary aggregate and create an
electro-conductive path. When the movement of carbon black in the
silicone rubber elastic layer is limited as described above, an
electro-conductive path becomes unlikely to be formed. As a result,
it is considered that a developing roller in which a
low-molecular-weight organic silane compound is added as an
adhesiveness-imparting component has an increased resistance, with
the result that appropriate conductivity cannot be obtained.
Thus, in order to allow a silicone rubber elastic layer and a
urethane resin layer to adhere to each other firmly without
impairing the conductivity of a developing roller, the inventors of
the present invention studied an adhesiveness-imparting component
capable of enhancing the adhesiveness between the urethane resin
layer and the silicone rubber elastic layer without inhibiting the
movement of carbon black.
As a result, the inventors of the present invention found that, by
forming a silicone rubber elastic layer of a cured product of an
addition polymerization type silicone rubber composition containing
an organopolysiloxane represented by the following formula (1), the
adhesive strength between the silicone rubber elastic layer and the
urethane resin can be enhanced without impairing the conductivity
of the silicone rubber elastic layer.
##STR00003##
In the formula (1), R.sup.1 represents an alkenyl group having 2 or
more and 4 or less carbon atoms, R.sup.2 represents a functional
group capable of reacting with an isocyanate group, and n
represents an integer of 1 or more.
The organopolysiloxane represented by the formula (1) has a
functional group R.sup.2 capable of reacting with an isocyanate
group at one terminal of a molecular chain. That is, the functional
group R.sup.2 is capable of being bonded to a functional group of a
material for a polyurethane resin contained in the resin layer.
Further, the organopolysiloxane represented by the formula (1) has
an alkenyl group at the other terminal of the molecular chain,
which is capable of forming a chemical bond with a cross-linking
network of silicone rubber through a hydrosilylation reaction.
Therefore, by using an addition polymerization type silicone rubber
composition containing the organopolysiloxane represented by the
formula (1) for forming an elastic layer, the adhesiveness between
the elastic layer and the resin layer can be enhanced.
Meanwhile, the function group R.sup.2 of the organopolysiloxane
represented by the formula (1) is also capable of reacting with a
functional group present on the surface of particles of carbon
black. Therefore, in the same way as in the case of using a
conventional low-molecular-weight organic silane compound, carbon
black is bonded to a cross-linking network of silicone rubber via a
molecular chain of the organopolysiloxane represented by the
formula (1).
However, the organopolysiloxane has a weight average molecular
weight Mw of 18,000 or more and 110,000 or less. Therefore, carbon
black can move freely to some degree even when being bonded to a
cross-linking network. As a result, formation of an
electro-conductive path is unlikely to be prevented, and a
developing roller having appropriate conductivity can be
produced.
It should be noted that the organopolysiloxane represented by the
formula (1) has a molecular weight distribution Mw/Mn (Mn
represents a number average molecular weight) of 1.0 or more and
2.0 or less. When the organopolysiloxane has such molecular weight
distribution, low-molecular-weight components which are liable to
inhibit the movement of carbon black and high-molecular-weight
components which are difficult to contribute to an adhesion
function can be reduced, and both expression of an appropriate
resistance and adhesiveness with a resin layer can be exhibited
sufficiently.
FIG. 1 is a cross-sectional view of a developing roller according
to an embodiment of a developing member of the present invention.
In a developing roller 4 in the figure, an elastic layer 2 and a
resin layer 3 are laminated in this order on an outer circumference
of a mandrel 1.
<Elastic Layer>
The addition polymerization type silicone rubber composition to be
used for the elastic layer is described below. The silicone rubber
composition as used herein refers to a resin material containing an
organopolysiloxane as a main raw material. As required, there may
be blended any of various additives, for example: an
electro-conductive agent such as carbon black; a filler such as
quartz powder, diatomaceous earth, dry silica, or wet silica; a
reaction inhibitor for adjusting a curing rate; a colorant; a
plasticizer; and a flame retarder. The silicone rubber composition
to be used in the present invention includes the following
components (a) to (d) as essential components.
(Component (a))
The component (a) of the silicone rubber composition is an
organopolysiloxane having two or more alkenyl groups bonded to a
silicon atom in one molecule and having a methyl group as a group
other than the alkenyl groups bonded to the silicon atom. It is
preferred that the component (a) have a weight average molecular
weight Mw of from 10,000 to 200,000. Examples of the alkenyl groups
include a vinyl group, an allyl group, a propenyl group, an
isopropenyl group, a butenyl group, an isobutenyl group, a pentenyl
group, and a hexenyl group. Of those, a vinyl group is preferred.
The alkenyl groups may be bonded to a silicon atom at a terminal or
in the middle of the molecular chain.
(Component (b))
The component (b) of the silicone rubber composition is an
organopolysiloxane having three or more hydrogen atoms bonded to a
silicon atom in one molecule and having a methyl group as a group
bonded to the silicon atom. It is preferred that the component (b)
have a weight average molecular weight Mw of from 300 to 100,000.
The hydrogen atoms of a hydrosilyl group may be bonded to a silicon
atom at a terminal or in the middle of the molecular chain. It is
preferred that the content of the component (b) be such an amount
that the molar ratio of hydrogen atoms bonded to the silicon atoms
of the component (b) with respect to the alkenyl groups bonded to
the silicon atoms contained in the components (a) and (e) fall
within the range of 1.0 or more and 5.0 or less.
(Component (c))
The component (c) of the silicone rubber composition is carbon
black for imparting conductivity and reinforcing property to the
elastic layer of the developing roller. In general, those which are
used as a conductivity-imparting agent of a silicone rubber
composition can be used. Examples of such carbon black include
acetylene black, furnace black, thermal black, and channel black.
In order to impart appropriate conductivity and reinforcing
property to the developing roller, it is preferred that the carbon
black have an average primary particle diameter of 10 nm or more
and 100 nm or less. It is also preferred that the carbon black have
a DBP oil-absorbing amount of 30 ml or more and 200 ml or less per
100 g. Further, two or more kinds of carbon blacks may be blended
depending on required physical properties. Further, in order for
the conductivity and reinforcing property of the developing roller
to fall within an appropriate range, it is preferred that the
content of the carbon black be 1 part by mass or more and 15 parts
by mass or less with respect to 100 parts by mass of the component
(a).
(Component (d))
The component (d) of the silicone rubber composition is a component
for imparting the adhesiveness with respect to the polyurethane
resin layer to the elastic layer of the developing roller. The
component (d) is an organopolysiloxane represented by the formula
(1) and having an alkenyl group at one terminal of its molecular
chain and a functional group capable of reacting with an isocyanate
group at the other terminal of the molecular chain. The
organopolysiloxane has a weight average molecular weight Mw of
18,000 or more and 110,000 or less and has a molecular weight
distribution Mw/Mn (Mn represents a number average molecular
weight) of 1.0 or more and 2.0 or less.
When the weight average molecular weight Mw of the component (d) is
18,000 or more, in the case where the functional group R.sup.2
reacts with a functional group on the surface of carbon black
particles, the movement of the carbon black particles is less
likely to be limited. Therefore, the resistance of the developing
roller can be prevented from remarkably increasing. Further, when
the weight average molecular weight Mw is 110,000 or less, the
number of the functional groups R.sup.2 per volume is sufficient,
and hence the elastic layer and the resin layer can adhere to each
other firmly.
When the molecular weight distribution Mw/Mn of the component (d)
is 1.0 or more and 2.0 or less, the ratios of a
low-molecular-weight component having a molecular weight of less
than 18,000 and a high-molecular-weight component having a
molecular weight of more than 110,000 become sufficiently low.
Therefore, the resistance of the developing roller can be set in an
appropriate range to allow the elastic layer and the resin layer to
adhere to each other firmly.
The component (d) has an alkenyl group R.sup.1 having 2 or more and
4 or less carbon atoms at one terminal of the molecular chain. It
is preferred that the alkenyl group be a vinyl group from the
viewpoint of reactivity. Further, the component (d) has a
functional group R.sup.2 capable of reacting with an isocyanate
group at the other terminal of the molecular chain, and examples of
the functional group include, but are not limited to, a hydroxyl
group, an alkoxyl group, an amino group, and a thiol group. A
hydroxyl group and an alkoxyl group are particularly preferred
because they are less likely to become a catalyst poison for a
hydrosilylation catalyst.
The functional groups R.sup.1 and R.sup.2 of the component (d) are
bonded to the respective terminals of the molecular chain.
Therefore, the functional groups are highly reactive and can impart
sufficient adhesiveness. Further, all the functional groups on the
side position of the molecular chain of the component (d) are
methyl groups. In a structure having organic groups other than the
methyl groups, the side position of the molecular chain becomes
bulky, and the movement of the molecular chain is liable to be
prevented in silicon rubber. As a result, when the silicone rubber
is bonded to carbon black particles, the movement of the carbon
black particles is limited, and sufficient conductivity is not
imparted to the developing roller.
The content of the component (d) is preferably 0.5 part by mass or
more and 10 parts by mass or less with respect to 100 parts by mass
of the component (a).
In this case, the weight average molecular weight Mw, the number
average molecular weight Mn, and the molecular weight distribution
Mw/Mn can be obtained through measurement using gel permeation
chromatography. Specifically, a high performance liquid
chromatography analyzer (HLC-8120GPC manufactured by TOSOH
CORPORATION) in which two GPC columns (TSKgel SuperHM-m
manufactured by TOSOH CORPORATION) are connected in series is used.
A measurement sample is a tetrahydrofuran (THF) solution at 0.1% by
mass, and is measured by using a refractive index (RI) detector
under the measurement conditions of a temperature of 40.degree. C.
and a flow rate of 0.6 ml/min. A calibration curve is prepared with
monodisperse standard polystyrenes (TSK standard polystyrenes
F-128, F-80, F-40, F-20, F-10, F-4, F-2, F-1, A-5000, A-2500,
A-1000, and A-500 manufactured by TOSOH CORPORATION) as standard
samples. The molecular weight distribution is obtained from the
retention time or number of counts of the measurement sample. Based
on the distribution, the weight average molecular weight Mw, the
number average molecular weight Mn, and the molecular weight
distribution Mw/Mn can be determined.
(Component (e))
It is preferred that a catalyst (hereinafter, sometimes referred to
as "component (e)") for promoting a hydrosilylation reaction
between the components (a) and component (d) and the component (b)
be blended in the silicone rubber composition containing the
components (a) to (d). As such catalyst, any of those which are
known as a catalyst for promoting a hydrosilylation reaction can be
used.
Examples of such catalyst include platinum-based, palladium-based,
and rhodium-based catalysts. Of those, a platinum-based catalyst is
preferred. As the platinum-based catalyst, for example, there are
used chloroplatinic acid, an alcohol solution of chloroplatinic
acid, a complex of chloroplatinic acid and an olefin, a complex of
chloroplatinic acid and vinylsiloxane, and a platinum-supported
silica. The addition amount of the catalyst is preferably such an
amount that the ratio of the mass of a catalyst metal atom with
respect to the mass of the component (a) falls within the range of
1 ppm or more and 100 ppm or less.
In the silicone rubber composition, in addition to the foregoing,
various known additives can also be used. For example, a reaction
inhibitor for adjusting a curing rate, a filler for imparting
reinforcing property, a colorant, a plasticizer, and a
flame-resistance-imparting agent may be added as necessary.
As a guideline, the thickness of the elastic layer is preferably
0.5 mm or more and 50 mm or less, more preferably 1 mm or more and
10 mm or less.
<Volume Resistivity of Elastic Layer>
It is preferred that the volume resistivity of the elastic layer be
1.times.10.sup.4 .OMEGA.cm or more and 1.times.10.sup.7 .OMEGA.cm
or less at a time of application of a DC voltage of 50 V. If the
volume resistivity of the elastic layer is 1.times.10.sup.4
.OMEGA.cm or more, even in the case where a bias is applied to a
developing blade, a blade bias leakage can be suppressed, and if
the volume resistivity of the elastic layer is 1.times.10.sup.7
.OMEGA.cm or less, the occurrence of a fogging image can be
suppressed. In this case, as the electrical resistance, a
measurement value obtained through use of an electrical resistance
measurement apparatus illustrated in FIG. 2 can be adopted.
An elastic roller 5 on which a resin layer is not formed is set in
abutment with a metal drum 6 having a diameter of 50 mm under the
application of a load of 4.9 N to each of both ends of a mandrel.
The metal drum 6 is rotated at a surface velocity of 50 mm/sec, and
the elastic roller 5 is driven following the rotation. A resistor R
having a known electrical resistance that is an electrical
resistance lower by two or more digits than the electrical
resistance of the elastic roller 5 is connected between the metal
drum 6 and the ground. A voltage of +50 V is applied from a
high-voltage power source HV to the mandrel of the elastic roller
5, and an electrical potential difference between both ends of the
resistor R is measured through use of a digital multimeter DMM (for
example, 189TRUE RMS MULTIMETER, manufactured by Fluke
Corporation). A current having flowed to the metal drum 6 through
the elastic roller 5 is calculated from the measured value of the
electrical potential difference and the electrical resistance of
the resistor R, and an electrical resistance of the elastic roller
5 is calculated from the current and the applied voltage of 50 V.
In the measurement using the digital multimeter, sampling is
performed for 3 seconds after the elapse of 2 seconds from the
application of the voltage, and a value calculated from an average
value thereof is defined as a resistance of the elastic layer.
Subsequently, an area of an abutment portion between the elastic
roller 5 and the metal drum 6 is calculated. A volume resistivity
of the elastic layer is determined from the resistance of the
elastic layer, the area of the abutment portion, and the thickness
of the elastic layer.
<Hardness of Elastic Layer>
The elastic layer is required to have appropriate elasticity as a
developing roller. Therefore, as the hardness of the elastic layer,
for example, an Asker C hardness of the elastic layer is preferably
10.degree. or more and 80.degree. or less. When the Asker C
hardness of the elastic layer is 10.degree. or more, the exudation
of an oil component from a rubber material constituting the elastic
layer can be suppressed, and the contamination of a photosensitive
drum can be suppressed. Further, when the Asker C hardness of the
elastic layer is 80.degree. or less, toner can be prevented from
being degraded, and image quality of an output image can be
prevented from decreasing.
In this case, the Asker C hardness can be defined by a measurement
value obtained by an Asker rubber hardness meter (manufactured by
Kobunshi Keiki Co., Ltd.) through use of a test chip separately
produced in accordance with Standard Asker C-type SRIS (Standard of
Nippon Rubber Society) 0101.
<Resin Layer>
The resin layer is described. The resin layer is formed of a
thermosetting polyurethane resin obtained by reacting an isocyanate
compound and a polyol compound.
Examples of the isocyanate compound include
diphenylmethane-4,4'-diisocyanate, 1,5-naphthalene diisocyanate,
3,3'-dimethylbiphenyl-4,4'-diisocyanate, 4,4'-dicyclohexylmethane
diisocyanate, p-phenylene diisocyanate, isophorone diisocyanate, a
carbodiimide-modified MDI, xylylene diisocyanate,
trimethylhexamethylene diisocyanate, tolylene diisocyanate,
naphthylene diisocyanate, p-phenylene diisocyanate, hexamethylene
diisocyanate, and polymethylene polyphenyl polyisocyanate. Those
isocyanate compounds may be used alone or in combination of two or
more kinds thereof.
Examples of the polyol compound include: divalent polyol compounds
(diols) such as ethylene glycol, diethylene glycol, propylene
glycol, dipropylene glycol, 1,4-butanediol, hexanediol,
neopentylglycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol,
xylene glycol, and tryethylene glycol; trivalent or more polyol
compounds such as 1,1,1-trimethylolpropane, glycerin,
pentaerythritol, and sorbitol; and high-molecular-weight polyol
compounds such as polyethylene glycol, polypropylene glycol, and
ethylene oxide-propylene oxide block glycol, which are obtained by
addition of ethylene oxide, propylene oxide to diols and triols.
Those polyol compounds may be used alone or in combination of two
or more kinds thereof.
It is preferred that the isocyanate compound be blended with the
polyol compound so that an isocyanate index falls within the range
of 1.1 or more and 1.5 or less. It should be noted that the
isocyanate index indicates a ratio ([NCO]/[OH]) between the molar
number of isocyanate groups in the isocyanate compound and the
molar number of hydroxyl groups in a polyol compound component. By
setting the isocyanate index in the range, the component (e)
contained in the elastic layer and the isocyanate compound of the
resin layer react with each other easily, with the result that high
adhesiveness is obtained, and an excess increase in hardness of the
resin layer can be suppressed.
The resin layer may contain the carbon black so as to impart
appropriate conductivity and reinforcing property. The carbon black
to be contained in the resin layer may be exemplified by those
which are similar to those exemplified as the carbon black to be
used in the elastic layer.
The resin layer may contain fine particles each having a volume
average particle diameter of 1 .mu.m or more and 20 .mu.m or less
so as to impart appropriate surface roughness to the surface of a
developing roller. Examples of the fine particles include plastic
pigments of polymethyl methylmethacrylate fine particles, silicone
rubber fine particles, polyurethane fine particles, polystyrene
fine particles, amino resin fine particles, and phenol resin fine
particles.
As a guideline, the thickness of the resin layer is preferably 1
.mu.m or more and 500 .mu.m or less, more preferably 1 .mu.m or
more and 50 .mu.m or less. When the thickness of the resin layer is
1 .mu.m or more, a developing roller can be obtained, which is
prevented from being degraded by wear or the like and is excellent
in durability. When the thickness of the resin layer is 500 .mu.m
or less, the surface of a developing roller does not have high
hardness easily, and degradation and sticking of toner can be
suppressed.
<Mandrel>
Any mandrel can be used as long as it has strength required for
supporting the elastic layer and the resin layer and conveying the
toner, and conductivity capable of serving as an electrode. As a
material for the mandrel, there may be given metals such as
aluminum, copper, stainless steel, and iron, or alloys thereof, or
an electro-conductive synthetic resin. Those materials may be
subjected to a plating treatment with chromium or nickel. It should
be noted that, for the purpose of allowing the mandrel and the
elastic layer formed on an outer side of the mandrel to adhere to
each other, a primer may be applied onto the mandrel. An example of
the primer is a silane coupling-based primer.
The size of the mandrel is not particularly limited, and the
mandrel has, for example, an outer diameter of 4 mm or more and 20
mm or less and a length of 200 mm or more and 380 mm or less.
FIG. 3 illustrates an example of a schematic configuration of an
electrophotographic apparatus including the developing roller of
the present invention. The image forming apparatus of FIG. 3
includes a developing device 10 including the developing roller 4,
a toner supply roller 7, toner 8, and a developing blade 9.
Further, the image forming apparatus includes a photosensitive drum
11, a charging roller 12, a cleaning blade 13, and a waste toner
accommodating container 14. The photosensitive drum 11 is rotated
in an arrow direction to be uniformly charged by the charging
roller 12 for charging the photosensitive drum 11, and an
electrostatic latent image is formed on the surface of the
photosensitive drum 11 with a laser beam 15 for writing an
electrostatic latent image on the photosensitive drum 11. The
electrostatic latent image is developed with the toner 8 provided
by the developing device 10 placed in contact with the
photosensitive drum 11 and visualized as a toner image. During the
development, so-called reversal development for forming a
negatively charged toner image on an exposure portion is
performed.
The visualized toner on the photosensitive drum 11 is transferred
onto an intermediate transfer belt 16 by a primary transfer roller
17. The toner image on the intermediate transfer belt 16 is
transferred onto a sheet 19 fed from a sheet feed roller 18 by a
secondary transfer roller 20. The sheet 19 with the toner image
transferred thereto is subjected to a fixing process by a fixing
device 21 and delivered outside the apparatus to complete a print
operation.
On the other hand, transfer residual toner remaining on the
photosensitive drum 11 without being transferred is scraped off
with the cleaning blade 13 that is a cleaning member for cleaning
the surface of the photosensitive drum to be accommodated in the
waste toner accommodating container 14. The thus cleaned
photosensitive drum 11 repeats the above-mentioned function.
The developing device 10 includes a developing container
accommodating the toner 8 and the developing roller 4 which is
positioned at an opening portion extending in a longitudinal
direction in the developing container and is set so as to be
opposed to the photosensitive drum 11, and is designed so as to
develop and visualize the electrostatic latent image on the
photosensitive drum 11.
A developing process in the developing device 10 is described
below. Toner is applied onto the developing roller 4 with the toner
supply roller 7 supported rotatably. The toner applied onto the
developing roller 4 is rubbed with the developing blade 9 due to
the rotation of the developing roller 4. The developing roller 4
comes into contact with the photosensitive drum 11 while rotating
and develops the electrostatic latent image formed on the
photosensitive drum 11 with the toner, with which the developing
roller 4 has been coated, to form an image.
As a structure of the toner supply roller 7, a foaming skeleton
sponge structure or a fur brush structure in which fibers of rayon,
polyamide, or the like are planted onto a mandrel is preferred from
the viewpoint of supplying the toner 8 to the developing roller 4
and scraping the undeveloped toner. For example, an elastic roller
in which a polyurethane foam is provided on a mandrel can be
used.
The abutment width of the toner supply roller 7 with respect to the
developing roller 4 is preferably 1 mm or more and 8 mm or less.
Further, it is preferred to cause the developing roller 4 to have a
relative velocity in the abutment portion.
EXAMPLES
The developing roller of the present invention is hereinafter
specifically described in detail.
Synthesis of an organopolysiloxane represented by the formula 1 and
having a functional group R.sup.1 at one terminal of a molecular
chain and having a functional group R.sup.2 at the other terminal
of the molecular chain is described.
(Synthesis of Organopolysiloxane (d-1))
0.24 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=50,000), and the composition was stirred at a temperature of
90.degree. C. for 4 hours. The resultant liquid was washed with
water, and remaining water was removed under reduced pressure. The
resultant was analyzed by gel permeation chromatography, and found
to have Mw=50,000 and Mw/Mn=1.5. Further, the presence of vinyl
groups and hydroxyl groups were confirmed by .sup.1H-NMR and
.sup.29Si-NMR analyses.
(Synthesis of Organopolysiloxane (d-2))
0.67 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=18,000), and synthesis and analysis were performed by the same
methods as those of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-3))
0.11 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=110,000), and synthesis and analysis were performed by the same
methods as those of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-4))
50 parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=10,000) were added to 50 parts by mass of hydroxy-terminated
polydimethylsiloxane (Mw=25,000). Further, 0.84 part by mass of
vinyldimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-5))
50 parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=40,000) were added to 50 parts by mass of hydroxy-terminated
polydimethylsiloxane (Mw=60,000). Further, 0.25 part by mass of
vinyldimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-6))
50 parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=100,000) were added to 50 parts by mass of hydroxy-terminated
polydimethylsiloxane (Mw=120,000). Further, 0.11 part by mass of
vinyldimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-7))
0.24 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=50,000). Further, 0.25 part by mass of
methoxydimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-8))
0.24 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=50,000). Further, 0.28 part by mass of
ethoxydimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-9))
0.24 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=50,000). Further, 0.22 part by mass of
aminodimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-10))
0.24 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=50,000). Further, 0.25 part by mass of
mercaptodimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-11))
0.67 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=18,000). Further, 0.69 part by mass of
methoxydimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-12))
0.11 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=110,000). Further, 0.11 part by mass of
methoxydimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-13))
50 parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=10,000) were added to 50 parts by mass of hydroxy-terminated
polydimethylsiloxane (Mw=25,000). Further, 0.84 part by mass of
vinyldimethylchlorosilane and 0.87 part by mass of
methoxydimethylchlorosilane were added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-14))
50 parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=40,000) were added to 50 parts by mass of hydroxy-terminated
polydimethylsiloxane (Mw=60,000). Further, 0.25 part by mass of
vinyldimethylchlorosilane and 0.26 part by mass of
methoxydimethylchlorosilane were added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-15))
0.67 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=18,000). Further, 0.77 part by mass of
ethoxydimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-16))
0.11 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=110,000). Further, 0.13 part by mass of
ethoxydimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-17))
0.67 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=18,000). Further, 0.61 part by mass of
aminodimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-18))
0.11 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=110,000). Further, 0.10 part by mass of
aminodimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-19))
0.67 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=18,000). Further, 0.70 part by mass of
mercaptodimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-20))
0.11 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=110,000). Further, 0.12 part by mass of
mercaptodimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-21))
0.30 part by mass of butenyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=50,000), and synthesis and analysis were performed by the same
methods as those of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-22))
0.83 part by mass of butenyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=18,000), and synthesis and analysis were performed by the same
methods as those of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-23))
0.14 part by mass of butenyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=110,000), and synthesis and analysis were performed by the same
methods as those of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-24))
0.30 part by mass of butenyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=50,000). Further, 0.25 part by mass of
methoxydimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-25))
0.30 part by mass of butenyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=50,000). Further, 0.28 part by mass of
ethoxydimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-26))
0.24 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=50,000). Further, 0.33 part by mass of
fluoromethyldimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-27))
1.20 parts by mass of vinyldimethylchlorosilane were added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=10,000), and synthesis and analysis were performed by the same
methods as those of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-28))
1.20 parts by mass of vinyldimethylchlorosilane were added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=10,000). Further, 1.25 parts by mass of
methoxydimethylchlorosilane were added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-29))
1.20 parts by mass of vinyldimethylchlorosilane were added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=10,000). Further, 1.39 parts by mass of
ethoxydimethylchlorosilane were added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-30))
1.20 parts by mass of vinyldimethylchlorosilane were added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=10,000). Further, 1.10 parts by mass of
aminodimethylchlorosilane were added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-31))
1.20 parts by mass of vinyldimethylchlorosilane were added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=10,000). Further, 1.27 parts by mass of
mercaptodimethylchlorosilane were added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-32))
0.09 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=140,000), and synthesis and analysis were performed by the same
methods as those of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-33))
0.09 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=10,000). Further, 0.09 part by mass of
methoxydimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-34))
0.09 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=10,000). Further, 0.10 part by mass of
ethoxydimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-35))
50 parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=5,000) were added to 50 parts by mass of hydroxy-terminated
polydimethylsiloxane (Mw=40,000). Further, 1.36 parts by mass of
vinyldimethylchlorosilane were added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-36))
50 parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=80,000) were added to 50 parts by mass of hydroxy-terminated
polydimethylsiloxane (Mw=150,000). Further, 0.12 part by mass of
vinyldimethylchlorosilane was added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-37))
50 parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=5,000) were added to 50 parts by mass of hydroxy-terminated
polydimethylsiloxane (Mw=40,000). Further, 1.36 parts by mass of
vinyldimethylchlorosilane and 1.40 parts by mass of
methoxydimethylchlorosilane were added to the composition, and
synthesis and analysis were performed by the same methods as those
of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-38))
0.33 part by mass of pentenyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydimethylsiloxane
(Mw=50,000), and synthesis and analysis were performed by the same
methods as those of the organopolysiloxane (d-1). Table 1 shows the
analysis results.
(Synthesis of Organopolysiloxane (d-39))
0.24 part by mass of vinyldimethylchlorosilane was added to 100
parts by mass of hydroxy-terminated polydiethylsiloxane
(Mw=50,000), and synthesis and analysis were performed by the same
methods as those of the organopolysiloxane (d-1).
(Synthesis of Organopolysiloxane (d-40))
0.56 part by mass of vinylmethyldichlorosilane was added to 100
parts by mass of hydroxy-terminated polydiethylsiloxane
(Mw=50,000). Further, 0.43 part by mass of trimethylchlorosilane
was added to the composition, and synthesis and analysis were
performed by the same methods as those of the organopolysiloxane
(d-1). Table 1 shows the analysis results of the
organopolysiloxanes (d-1 to d-40).
TABLE-US-00001 TABLE 1 Functional group other Position of than
R.sup.1 and Organopolysiloxane Mw Mw/Mn R.sup.1 R.sup.2 R.sup.1
R.sup.2 d-1 50,000 1.5 Vinyl Hydroxyl Molecular Methyl group d-2
18,000 1.5 chain d-3 110,000 1.5 terminal d-4 18,000 2.0 d-5 50,000
2.0 d-6 110,000 2.0 d-7 50,000 1.5 Methoxy d-8 50,000 1.5 Ethoxy
d-9 50,000 1.5 Amino d-10 50,000 1.5 Mercapto d-11 18,000 1.5
Methoxy d-12 110,000 1.5 d-13 18,000 2.0 d-14 50,000 2.0 d-15
18,000 1.5 Ethoxy d-16 110,000 1.5 d-17 18,000 1.5 Amino d-18
110,000 1.5 d-19 18,000 1.5 Mercapto d-20 110,000 1.5 d-21 50,000
1.5 Butenyl Hydroxyl d-22 18,000 1.5 d-23 110,000 1.5 d-24 50,000
1.5 Methoxy d-25 50,000 1.5 Ethoxy d-26 50,000 1.5 Vinyl
Fluoromethyl d-27 10,000 1.5 Hydroxyl d-28 10,000 1.5 Methoxy d-29
10,000 1.5 Ethoxy d-30 10,000 1.5 Amino d-31 10,000 1.5 Mercapto
d-32 140,000 1.5 Hydroxyl d-33 140,000 1.5 Methoxy d-34 140,000 1.5
Ethoxy d-35 22,000 3.0 Hydroxyl d-36 110,000 3.0 d-37 22,000 3.0
Methoxy d-38 50,000 1.5 Pentenyl Hydroxyl d-39 50,000 1.5 Vinyl
Ethyl group d-40 50,000 1.5 Moecular Methyl group chain non-
terminal
Example 1
(Formation of Elastic Layer)
A mandrel was obtained by applying a primer (trade name: DY35-051,
manufactured by Dow Corning Toray Co., Ltd.) onto a cored bar with
a diameter of 6 mm made of stainless steel SUS304 and baking the
resultant at a temperature of 150.degree. C. for 30 minutes. Then,
the mandrel was placed concentrically with respect to a cylindrical
mold with an inner diameter of 11.5 mm, and an addition reaction
type silicone rubber composition obtained by mixing the components
(a) to (e) described in Table 2 was injected into a cavity created
in the mold.
TABLE-US-00002 TABLE 2 (a) Vinyl-terminated polydimethylsiloxane
DMS-V42 100 parts (trade name, manufactured by GELEST, INC.) by
mass (b) Methylhydrosiloxane HMS-301 5 parts by (trade name,
manufactured by GELEST, INC.) mass (c-1) Carbon Black, Denka Black
Powdery Product 2 parts by (trade name, manufactured by DENKI
KAGAKU KOGYO mass CO., LTD.) (c-2) Carbon Black SUNBLACK235 6 parts
by (trade name, manufactured by ASAHI CARBON CO., mass LTD. ) (d)
Organopolysiloxane (d-1) 1 part by mass (e)
Platinum-cyclovinylmethylsiloxane complex 0.05 part SIP6832.2 by
mass (trade name, manufactured by GELEST, INC.)
In Table 2, the weight average molecular weight of the component
(b) is 1,900 to 2,000.
Subsequently, the mold was heated to vulcanize and cure the
unvulcanized silicone rubber composition at a temperature of
150.degree. C. for 15 minutes, and the resultant silicone rubber
composition was cooled and released from the mold. After that, the
silicone rubber composition was further heated at a temperature of
200.degree. C. for 2 hours to complete a curing reaction, and an
elastic layer was provided around the mandrel.
(Synthesis of Polyol)
20 parts by mass of an isocyanate compound Millionate MT (trade
name, manufactured by Nippon Polyurethane Industry Co., Ltd.) were
mixed with 100 parts by mass of polytetramethylene glycol PTG1000SN
(trade name, manufactured by Hodogaya Chemical Co., Ltd.) in stages
in a methyl ethyl ketone (MEK) solvent. The mixed solution was
subjected to a reaction at a temperature of 80.degree. C. for 7
hours in a nitrogen atmosphere to produce the polyether polyol with
a hydroxyl value of 20 [mgKOH/g].
(Synthesis of Isocyanate)
In a nitrogen atmosphere, 57 parts by mass of crude diphenylmethane
diisocyanate (MDI, trade name: Cosmonate M-200, manufactured by
Mitsui Chemicals Polyurethanes, Inc.) were mixed with 100 parts by
mass of polypropylene glycol with a number average molecular weight
of 400 (trade name: Excenol, manufactured by Asahi Glass Co.,
Ltd.), and the composition was subjected to a heating reaction at a
temperature of 90.degree. C. for 2 hours. After that, butyl
cellosolve was added to the resultant so that the solid content
became 70% to obtain an isocyanate compound in which the mass ratio
of an NCO group contained per solid content was 5.0% by mass. Then,
22 parts by mass of MEK oxime were added dropwise under a condition
of a reactant temperature of 50.degree. C. to obtain a block
polyisocyanate.
(Production of Resin Layer Coating Material (1))
The block polyisocyanate was mixed with the polyol produced as
described above so that the NCO/OH group ratio became 1.4. With
respect to 100 parts by mass of a resin solid content of the
composition, 20 parts by mass of carbon black (trade name: MA100,
manufactured by Mitsubishi Chemical Corporation, pH=3.5) and 30
parts by mass of urethane resin particles (trade name: C400
transparent, manufactured by Negami Chemical Industrial Co., Ltd.,
average particle diameter: 14 .mu.m) were added, and the
composition was dissolved and mixed in MEK so that the total solid
content became 35% by mass. The mixed solution was dispersed with a
sand mill for 4 hours through use of glass beads with a particle
diameter of 1.5 mm to obtain a resin layer coating material
(1).
(Formation of Resin Layer on Elastic Layer)
The resin layer coating material 1 obtained as described above was
applied onto the elastic layer by dip coating through use of an
overflow type dip coating apparatus. The resin layer coating
material was dried with air at room temperature for 30 minutes and
then subjected to a heat treatment in a hot air circulation oven at
140.degree. C. for 2 hours to obtain a developing roller having a
resin layer with a thickness of 12 .mu.m on the surface of the
elastic layer.
(Evaluation of Adhesiveness between Elastic Layer and Resin
Layer)
Adhesiveness was evaluated by observing film peeling between an
elastic layer and a resin layer of a developing roller. The
developing roller was left to stand in an environment of a
temperature of 40.degree. C. and a humidity of 95% RH for 30 days.
After that, the developing roller was further left to stand in an
environment of a temperature of 23.degree. C. and a humidity of 50%
RH for 24 hours. After the developing roller was left to stand, a
peeling test was performed by pressing a cellophane adhesive tape
onto a 2-mm crosscut grid in accordance with JIS K5600-5-6 in the
same environment, and adhesiveness between the elastic layer and
the resin layer was evaluated based on the criteria shown in Table
3.
TABLE-US-00003 TABLE 3 A The peeling of the resin layer on the
crosscut surface is less than 5%. B The peeling of the resin layer
on the crosscut surface is 5% or more and less than 35%. C The
peeling of the resin layer on the crosscut surface is 35% or
more.
(Evaluation of Fogging)
The developing roller obtained in Example 1 was incorporated into a
process cartridge (trade name: CRG-316BLK, manufactured by Canon
Inc.) in a laser printer (trade name: LBP5050, manufactured by
Canon Inc.) having a configuration as illustrated in FIG. 3, and a
fogged image was evaluated.
In an environment of a temperature of 30.degree. C. and a humidity
of 80% RH, 3,000 sheets of an image having a printing ratio of 1%
were successively output, and thereafter, a white solid image was
output. The degree of fogging (fogging value) of the output white
solid image was measured by the following method to be 0.5%.
Regarding the fogging value, a reflection density of a transfer
sheet before formation of an image and a reflection density of a
transfer sheet after a white solid image was formed were measured
through use of a reflection densitometer (trade name: TC-6DS/A,
manufactured by Tokyo Denshoku Co., Ltd.) and a difference between
the reflection densities was defined as a fogging value of the
developing roller. Regarding measurement of a reflection density,
the entire region of an image printing area on a transfer sheet was
scanned to measure a reflection density and a minimum value thereof
was defined as a reflection density of the transfer sheet.
In a developing roller having a remarkably high resistance, a
development field formed between the developing roller and a
photosensitive drum cannot be controlled appropriately. When a
white solid image is formed through use of such developing roller,
a part of toner moves onto the photosensitive drum. Further, when
the toner is transferred onto a transfer sheet, fogging is caused.
Thus, by evaluating a fogged image, whether or not a resistance of
the developing roller is appropriate can be evaluated.
The fogging value was evaluated based on the criteria shown in
Table 4. In this case, the following evaluations A and B indicate
levels without any practical problems. On the other hand, an
evaluation C indicates a level at which "fogging" can be apparently
recognized by visual inspection.
TABLE-US-00004 TABLE 4 A The fogging value is less than 1.0. B The
fogging value is 1.0 or more and less than 3.0. C The fogging value
is 3.0 or more.
Examples 2 to 25
The same method as that of Example 1 was performed except that the
organopolysiloxane (d-1) was changed to the organopolysiloxanes
shown in Table 5 below, and various evaluations were performed.
Table 5 shows the results.
Examples 26 to 33
The same method as that of Example 1 was performed except that the
organopolysiloxane (d-1) was changed to the organopolysiloxanes
shown in Table 5 below and the resin layer coating material (1) was
changed to the following resin layer coating material (2), and
various evaluations were performed. Table 5 shows the results.
(Production of Resin Layer Coating Material (2))
The same method as that of the resin layer coating material 1 was
performed except that the block polyisocyanate was mixed with the
polyol so that the NCO/OH group ratio became 1.1 in the production
of the resin layer coating material (1). Thus, a resin layer
coating material (2) was obtained.
Comparative Example 1
The same method as that of Example 1 was performed except that an
elastic layer was formed without adding the organopolysiloxane
(d-1), and various evaluations were performed. Table 6 shows the
results.
Comparative Example 2
The same method as that of Example 1 was performed except that the
organopolysiloxane (d-1) was changed to the organopolysiloxane
(d-26), and various evaluations were performed. Table 6 shows the
results.
Comparative Example 3
The same method as that of Example 1 was performed except that the
organopolysiloxane (d-1) was changed to trimethoxyvinylsilane, and
various evaluations were performed. Table 6 shows the results.
Comparative Examples 4 to 17
The same method as that of Example 1 was performed except that the
organopolysiloxane (d-1) was changed to the organopolysiloxanes
shown in Table 6 below, and various evaluations were performed.
Table 6 shows the results.
TABLE-US-00005 TABLE 5 Resin Volume Component (d) in layer
resistivity elastic layer NCO/OH of elastic Organopoly- group
Adhesive- layer Fog- Example siloxane ratio ness (.OMEGA. cm) ging
1 d-1 1.4 A 4.8 .times. 10.sup.5 A 2 d-2 A 8.1 .times. 10.sup.5 A 3
d-3 A 4.2 .times. 10.sup.5 A 4 d-4 A 1.4 .times. 10.sup.5 A 5 d-5 A
5.8 .times. 10.sup.5 A 6 d-6 B 4.5 .times. 10.sup.5 A 7 d-7 A 4.7
.times. 10.sup.5 A 8 d-8 A 4.1 .times. 10.sup.5 A 9 d-9 A 5.6
.times. 10.sup.5 A 10 d-10 A 6.4 .times. 10.sup.5 A 11 d-11 A 7.7
.times. 10.sup.5 A 12 d-12 A 4.9 .times. 10.sup.5 A 13 d-13 A 9.7
.times. 10.sup.5 A 14 d-14 A 6.1 .times. 10.sup.5 A 15 d-15 A 6.8
.times. 10.sup.5 A 16 d-16 B 3.8 .times. 10.sup.5 A 17 d-17 A 8.2
.times. 10.sup.5 A 18 d-18 B 5.5 .times. 10.sup.5 A 19 d-19 A 9.5
.times. 10.sup.5 A 20 d-20 B 6.1 .times. 10.sup.5 A 21 d-21 B 5.0
.times. 10.sup.5 A 22 d-22 B 7.7 .times. 10.sup.5 A 23 d-23 B 5.1
.times. 10.sup.5 A 24 d-24 B 4.4 .times. 10.sup.5 A 25 d-25 B 4.1
.times. 10.sup.5 A 26 d-1 1.1 A 4.8 .times. 10.sup.5 A 27 d-2 A 8.1
.times. 10.sup.5 A 28 d-3 B 4.2 .times. 10.sup.5 A 29 d-5 A 5.8
.times. 10.sup.5 A 30 d-7 A 4.7 .times. 10.sup.5 A 31 d-8 A 4.1
.times. 10.sup.5 A 32 d-9 A 5.6 .times. 10.sup.5 A 33 d-10 A 6.4
.times. 10.sup.5 A
TABLE-US-00006 TABLE 6 Resin Volume Component (d) in layer
resistivity Compar- elastic layer NCO/OH of elastic ative
Organopoly- group Adhesive- layer Fog- Example siloxane ratio ness
(.OMEGA. cm) ging 1 -- 1.4 C 3.9 .times. 10.sup.5 A 2 d-26 C 1.1
.times. 10.sup.6 B 3 Trimethoxy- A 1.9 .times. 10.sup.8 C
vinylsilane 4 d-27 A 7.9 .times. 10.sup.7 C 5 d-28 A 5.3 .times.
10.sup.7 C 6 d-29 A 5.9 .times. 10.sup.7 C 7 d-30 A 6.1 .times.
10.sup.7 C 8 d-31 A 3.6 .times. 10.sup.7 C 9 d-32 C 4.2 .times.
10.sup.5 A 10 d-33 C 3.6 .times. 10.sup.5 A 11 d-34 C 3.2 .times.
10.sup.5 A 12 d-35 A 2.8 .times. 10.sup.7 C 13 d-36 A 4.4 .times.
10.sup.7 C 14 d-37 C 8.8 .times. 10.sup.5 A 15 d-38 C 4.4 .times.
10.sup.5 A 16 d-39 B 3.1 .times. 10.sup.7 C 17 d-40 C 9.8 .times.
10.sup.6 B
In Examples 1 to 33, each developing roller had a configuration
defined by the present invention. Thus, an elastic layer made of a
cured product of a silicone rubber composition and a resin layer
made of a thermosetting polyurethane resin adhered to each other
firmly. Further, the conductivity of the developing roller was not
impaired, and consequently, a satisfactory image with fogging
suppressed was obtained.
On the other hand, the adhesiveness between the elastic layer and
the resin layer was insufficient in the developing roller of
Comparative Example 1. This is because the elastic layer did not
contain the component (d) for imparting adhesiveness. The
adhesiveness between the elastic layer and the resin layer was
insufficient also in the developing roller of Comparative Example
2. This is because the component (d) added to the elastic layer had
no functional group capable of reacting with the isocyanate
compound in the resin layer.
The developing rollers of Comparative Examples 3 to 8 had a high
resistance and poor results of fogging evaluation. The reason for
this is considered as follows: the molecular weight of the
organopolysiloxane added as the component (d) was too small, which
prevented the formation of an electro-conductive path. Further, in
the developing rollers of Comparative Examples 9 to 11, the
adhesiveness between the elastic layer and the resin layer was
insufficient. The reason for this is considered as follows: the
molecular weight of the organopolysiloxane added as the component
(d) was too large, with the result that a sufficient chemical bond
was not able to be formed.
The developing rollers of Comparative Examples 12 and 13 had a high
resistance and poor results of fogging evaluation. The reason for
this is considered as follows: the content of components having a
molecular weight of less than 18,000 became too large owing to
large Mw/Mn, which prevented the formation of an electro-conductive
path. Further, in the developing roller of Comparative Example 14,
the adhesiveness between the elastic layer and the resin layer was
insufficient. The reason for this is considered as follows: the
content of components having a molecular weight of more than
110,000 became too large owing to large Mw/Mn, with the result that
a sufficient chemical bond was not able to be formed.
In the developing roller of Comparative Example 15, the
adhesiveness between the elastic layer and the resin layer was
insufficient. The reason for this is considered as follows: the
number of carbons of alkenyl groups of the component (d) was too
large, with the result that a sufficient chemical bond was not able
to be formed. The developing roller of Comparative Example 16 had a
high resistance and poor results of fogging evaluation. The reason
for this is considered as follows: all the functional groups other
than R.sup.1 and R.sup.2 of the component (d) were ethyl groups,
and hence a degree of freedom of molecular movement became small,
which inhibited the formation of an electro-conductive path.
In the developing roller of Comparative Example 17, the
adhesiveness between the elastic layer and the resin layer was
insufficient. The reason for this is considered as follows: the
functional groups R.sup.1 and R.sup.2 of the component (d) were
positioned at molecular chain non-terminals, with the result that a
sufficient chemical bond was not able to be formed.
REFERENCE SIGNS LIST
1 mandrel 2 elastic layer 3 resin layer 4 developing roller 5
elastic roller 6 metal drum 7 toner supply roller 8 toner 9
developing blade 10 developing device 11 photosensitive drum 12
charging roller 13 cleaning blade 14 waste toner accommodating
container 15 laser beam 16 intermediate transfer belt 17 primary
transfer roller 18 sheet feed roller 19 sheet 20 secondary transfer
roller 21 fixing device
While the present invention has been described with reference to
exemplary embodiments, it is to be understood that the invention is
not limited to the disclosed exemplary embodiments. The scope of
the following claims is to be accorded the broadest interpretation
so as to encompass all such modifications and equivalent structures
and functions.
This application claims the benefit of Japanese Patent Application
No. 2011-270638 filed on Dec. 9, 2011 and Japanese Patent
Application No. 2012-249648 filed on Nov. 13, 2012, which are
hereby incorporated by reference herein in their entirety.
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